Apparatus for cutting a sheet material

ABSTRACT

An apparatus for cutting a sheet material comprising a barshaped cutter receiving member disposed to extend across the width of the sheet material in contact with one surface thereof and an annular cutter whose center axis is nearly normal to an edge of the cutter receiving member. The sheet material can be cut by the annular cutter as the latter is rolled with a portion of its peripheral edge maintained in pressing engagement with the edge of the cutter receiving member.

United States Patent Fujimoto 1 51 Aug. 29, 1972 [54] APPARATUS FORCUTTING A SHEET MATERIAL [72] Inventor: Salraehflimoto, Tokyo, Japan[73] Assignee: Kabushiki-Kaisha Rlcoh,

Japan [22] Filed: Feb. 5, 1970 [2]] Appl. No; 8,924

Tokyo,

301 Foreign Application Priority om Feb. 20, 1969 Japan......................44/l3085 52 us. c1. ..s3/4s2, 83/487, 83/564,83/582, 83/614 51 Int. (:1. ..B26d 1/20 [58] Field of Search..83/485489, 614, 83/353, 564, 482

[56] References Cited UNITED STATES PATENTS 3,282,140 11/1966Sasabuchietal.... ....3/353X 3,221,585 12/1965 Staar 83/614 X FOREIGNPATENTS 0R APPLICATIONS 180,251 1/1907 Germany ..83/487 719,649 4/1942Germany ..83/485 Primary Examiner-Andrew R. Juhasz Attorney-McGlew andToren [57] ABSTRACT Anapparatus for cutting a sheet material comprisinga bar-shaped cutter receiving member dispoaed to extend across the widthof the sheet material in contact with one surface thereof and an annularcutter whose center axis is nearly normal to an edge of the cutterreceiving member. The sheet material can be cut by the annular cutter asthe latter is rolled with a portion of its peripheral edge maintained inpressing engagement with the edge of the cutter receiving member.

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Tn IINEY APPARATUS FOR CU'I'IING A SHEET MATERIAL BACKGROUND OF THEINVENTION In copiers and other machines which use a roll ofphotosensitive sheet material or a roll of recording sheet material,there is generally provided an apparatus for cutting such sheet materialafter it is paid out from the roll.

One apparatus for cutting a sheet material used with a copier known inthe art comprises a fixed cutter 2 disposed over one surface of thephotosensitive sheet material I paid out from the roll and arranged toextend along the width thereof, and a movable cutter 3 disposed belowthe other surface of the photosensitive sheet material I to cooperatewith the fixed cutter 2 as shown in FIG. 1. The photosensitive sheetmaterial is cut by a cutting edge of the fixed cutter and a cutting edge30 of the movable cutter as the movable cutter 3 is rotated in thedirection of the arrow A. A

The prior art apparatus for cutting a sheet material referred tohereinabove has disadvantages. The operation of replacing the cutters,particularly the movable cutter, with new cutters is troublesome andtime consuming when the cutting edges of old cutters are worn. Themovable cutter is high in cost. The resistance of the sheet materialmarkedly increases as the cutting edges of the cutters are worn. Thistype of sheet material cutting apparatus has a short service life whenit is used for cutting a magnetic sheet material for transferringmagnetic recordings because it is required to cut a large number ofsheets from a roll of magnetic sheet material in this case.

SUMIMARY OF THE INVENTION This invention relates to apparatus forworking on paper, fabric and other sheet material and deals moreparticularly with an improved apparatus for cutting a sheet material.

An object of this invention is to provide an improved apparatus forcutting a sheet material which obviates all the disadvantages of priorart apparatus for cutting a sheet material.

Another object of the invention is to provide an apparatus of the typedescribed in which an annular cutter used as a movable cutter can bemade to operate effectively as it is moved along a cutter receivingmember which cooperates with it.

Another object of the invention is to provide means for supporting theannular cutter which permits to effect adjustments of the angle ofcontact between the annular cutter and the cutter receiving member so asto provide the most satisfactory cutting effect.

Additional objects as well as features and advantages of the inventionwill become evident from the description set forth hereinafter whenconsidered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showingessential portions of a prior art apparatus for cutting a sheetmaterial.

FIG. 2 is a schematic perspective view in explanation of the cuttingoperation of the apparatus according to this invention;

FIG. 3 is a plan view of FIG. 2;

FIG. 4 is a side view of FIG. 2 as seen from the side on which theannular cutter is disposed, with the sheet material shown in FIG. 2being omitted;

FIG. 5 is a front view showing the relative positions of the annularcutter and the cutter receiving member;

FIG. 6 is a plan view of one embodiment of the cutter receiving memberused for cutting a sheet material while the latter is moved;

FIG. 7 is a side view of the apparatus for cutting a sheet materialcomprising one embodiment of this invention;

FIG. 8 is a side view of FIG. 7 showing the annular cutter being madeready for performing a sheet material cutting operation in its startingposition;

FIG. 9 is an enlarged sectional view taken along the line A-A of FIG. 8;

FIG. l0is a plan view showing a portion of FIG. 7;

FIG. 1 1 is a perspective view of means for supporting the annularcutter; and

FIG. 12 is a perspective view of one embodiment of the drive means formoving the annular cutter in reciprocating motion.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings whichillustrate the preferred embodiments of this invention, like referencecharacters designate similar or corresponding parts. An annular cutter 4is firmly fixed, by a clamping nut 8, to the outer circumferentialsurface of a cylindrical member 7 which includes a slightly convex outercircumferential portion 7a (See FIG. 9). Fitted in the bore of thecylindrical member 7 is an outer race of a ball bearing which is securedto the inner wall of the cylindrical member 7 by means of a threadedring 10 threadably received in the outer opening of the cylindricalmember 7. The ball bearing comprises an inner race 9b which isthreadably connected, by means of a headed screw 13, to the outer end ofa shaft 12 which is loosely fitted, at the inner end, in an openingformed in a spherical member 11. Thus, the cylindrical member 7 to whichthe annular cutter 4 is attached can rotate freely about the shaft 12.

The spherical member 11 supporting the inner end of the shaft 12 isfirmly held between a pivotal plate 16 pivotally connected by a shaft 15to a first side wall 14a of a sliding member 14 and a keep plate 18firmly fixed at opposite ends to the pivotal plate 16 by means of twoscrews 17, 17. Since the inner end of the shaft 12 is supported by thespherical member 11, it is posible to adjust the direction of the centeraxis of rotation of the annular cutter 4 so as to provide the mostsatisfactory sheet cutting effect. The direction in which the shaft 12is disposed can be adjusted by slightly loosening the screws 17,17 toprovide latitude for rotation of the spherical member 11. Preferably,the shaft 12 which is coaxial with the center axis of rotation of theannular cutter 4 is inclined slightly at a minute angle with respect toa perpendicular to a lateral surface 50 of a cutter receiving member 5so that a sharp wedgeshaped space S may be formed between the lateralsurface 5a and the peripheral edge of the annular cutter 4 as shown inFIG. 3.

An expansive spring 19 mounted between the pivotal plate 16 and a flange12a (See FIG. 9) of the shaft 12 biases the shaft 12 outwardly (to theright in FIG. 9) so that a portion of the peripheral edge of the annularcutter 4 presses against the lateral surface 5a of the cutter receivingmember 5. The cutter receiving member 5 is mounted on the upper part ofone side of a rigid supporter 20 fixed to an immovable frame of theapparatus and caused to press thereagainst by a bent lateral edge 21a ofa keep plate 21 which is attached to the one side of the supporter 20 bya number of screws 22,22. The bent lateral edges 21a and 21b straddlethe cutter receiving member 5 and its supporter 20, so that the cutterreceiving member 5 bears strongly against the supporter 20 and is fixedthereto when the screws 22,22 are tightened. The cutter receiving member5 has an upper end surface 5b which is substantially on the same levelas a planar upper surface 200 of the supporter 20.

The convex outer circumferential portion 7a of the cylindrical member 7moves in rolling motion on the planar upper surface 200 of the supporter20 during the process of cutting a sheet material by the annular cutter4 in cooperation with the cutter receiving member 5. The convex outercircumferential portion 7a serves to cause the sheet material to pressagainst the planar upper surface 200 of the supporter 20 and to keepconstant the amount of overlapping of the annular cutter 4 and cutterreceiving member 5.

A second side wall 14b of the sliding member 14 to which the pivotalplate 16 is pivotally connected (See FIG. 11) is formed with an opening23 and a cutout 24, and a third side wall 14c thereof of smaller widthis formed with an opening 25 which is aligned with the opening 23. Afirst guide rod 26 loosely extends through the cutout 24, and a secondguide rod 27, which is parallel to the first guide rod 26, looselyextends through the aligned openings 23 and 25 (See FIG. 12). Thesliding member 14 is adapted to move in sliding motion over the guiderods 26 and 27 which are secured at opposite ends to the immovable frameof the apparatus. Preferably, bearings providing a friction reducingeffect are mounted in the openings 23 and 25 and cutout 24 forjoumalling the guide rods 26 and 27 to prevent the openings and cutoutfrom coming into direct contact with the guide rods, so that the slidingmember 14 may be able to move smoothly over the guide rods 26 and 27.

A wire 29 trained substantially parallel to the guide rod 27 is fastenedin its intermediate portion to a pin 28 connected to the pivotal plate16 in a position above the shaft 15. FIG. 7 shows the wire 29 as it ispulled to the left, and FIG. 8 shows the wire 29 as it is begun to bepulled to the right. Ifthe wire 29 is pulled to the left, the pivotalplate 16 will be moved in pivotal motion in an anticlockwise directionabout the shaft till its vertex 16a abuts against a projection 14dformed in the sliding member 14. As the pivotal plate 16 is moved asaforementioned, the annular cutter 4 is released from engagement withthe cutter receiving member 5. Since the annular cutter 4 is normallybiased outwardly by the spring 19 (See FIG. 9), the annular cutter 4tends to be disposed above the cutter receiving member 5 when the formeris released from the latter as shown in FIG. 7. This tendency isprevented by a pusher plate 30 mounted in a position in which it isjuxtaposed to the outer end of the cylindrical member 7. As shown inFIG. 10, the pusher plate 30 extends to be increasingly spaced apartfrom the outer end of the cylindrical member 7, so that when thecylindrical member 7 moves in rolling motion from the right in FIG. 10the pusher plate 30 receives and stops the cylindrical member 7. Thepusher plate 30 includes a downwardly extending portion 304 which isfixed to the rear side of the supporter 20 by means of screws 31,31.Thus, the pusher plate 30 is disposed at one end of the supporter 20which is a starting position of the annular cutter 4.

As shown in FIG. 12, the wire 29 is attached at one end to a pulley 32of relatively larger diameter and at the other end to a peripheralgroove of a pulley 33 of substantially the same dimension as the pulley32. The wire 29 is trained over intermediate pulleys 34 and 35 ofsmaller diameter so as to maintain the length of wire between the twointermediate pulleys 34 and 35 parallel to the guide rod 27. Theintermediate pulleys also serve to guide the wire 29 so that theopposite ends of the wire are directed to the respective larger diameterpulleys. A length 29a of the wire 29'clisposed between the intermediatepulley 34 and larger diameter pulley 32 and a length 29b of the wire 29disposed between the intermediate pulley 35 and larger diameter pulley33 are inclined in opposite directions. The larger diameter pulleys 32and 33 are secured to opposite ends of a pulley shaft 37 having a gear36 mounted near one end thereof which gear 36 is adapted to beoscillated by suitable drive means (not shown) without making a completerevolution in either direction.

In operation, if the gear 36 is rotated in the direction of the arrow inFIG. 12, the pulleys 32 and 33 will rotate in conjunction with eachother in the direction of the arrow, with the pulley 32 winding the wire29 thereon as the wire is paid out by the pulley 33. The wire 29 pullsand moves in the direction of the arrow the pivotal plate 16 carryingthe annular cutter 4, so that a sheet material 38 disposed on the cutterreceiving member 5 is cut by the annular cutter 4 as it moves thereoverin rolling motion. Immediately before the pivotal plate 16 begins to bepulled and moved by the wire 29, the pivotal plate 16 is moved inpivotal motion in a clockwise direction about the shaft 15 as shown inFIG. 8 so as to bring the convex outer circumferential portion intocontact with the supporter 20 (See FIG. 9). As the pivotal plate 16 ismoved as aforementioned, the annular cutter 4 is spaced apart from thelateral surface of the cutter receiving member 5 as shown in FIG. 10. Ifthe pivotal plate 16 is pulled to the right by the wire 29 at this time,then the end edge 7b of the convex outer circumferential portion 7a ismoved away from the pusher plate 30, so that the annular cutter 4 whichis substantially integral with the convex outer circumferential portion7a is urged to move outwardly by the biasing force of spring 19. Thus,the peripheral edge of the annular cutter 4 is caused to press againstthe upper portion of the lateral surface of the cutter receiving member5 as shown in FIG. 9. The sheet material can be cut as the pivotal plate16 is pulled by the wire 29 while the annular cutter 4 and cutterreceiving member 5 are maintained in this state.

When the annular cutter 4 has moved to the end of the cutter receivingmember 5 after the sheet material is cut, the direction of rotation ofthe gear 36 (See FIG. 12) is reversed so as to move the pivotal plate 16in an opposite direction. Means for reversing the direction of movementof the gear 36 may be of any suitable type available. Such means mayinclude a microswitch disposed in a position in which the slidingmovement of the sliding member 14 comes to an end, which microswitch isactuated when a portion of the sliding member is brought into contactwith the actuating member of the microswitch so as to reverse thedirection of rotation of the electric motor. Altematively, a clutch of aconventional type may be used to change the directions of movement ofthe sliding member.

If the pivotal plate 16 is pulled and moved in an opposite direction bythe wire 29 after the sheet material is cut, the pivotal plate 16 willbe moved in pivotal motion about the shaft 15 and its vertex 160 (SeeFIG. 7) will abut against the projection 14d before the sliding member14 pivotally mounting the pivotal plate 16 is pulled and moved, and thenthe pivotal plate 16 and sliding member 14 will be pulled and moved inthe opposite direction as a unit. when the sliding member 14 is restoredto a position shown in FIG. 7, the sliding member 14 produces a commandto shut off the wire driving means. During the return movement of thepivotal plate, the annular cutter 4 is maintained in a position in whichit is spaced apart from the cutter receiving member 5. This permits toadvance the sheet material to the next cutting position while themembers including the annular cutter are moved to the starting position.The annular cutter 4 is biased outwardly by the spring 19 while it isspaced apart form the cutter receiving member 5. However, if the membersincluding the annular cutter are restored to the starting position shownin H6. 10, then the end edge 7b of the convex outer circumferentialportion 7a is pushed inwardly by the pusher plate 30. Thus, the annularcutter 4 is prevented from striking the cutter receiving member 5 whenit is moved again.

If it is required to cut a sheet material disposed over the cutterreceiving member while moving the sheet material in one direction, asshown in FIG. 6, one edge of the cutter receiving member 5 has only tobe inclined relative to a line drawn across the width of the sheetmaterial 39. In this case, the rate of movement Vp of the sheetmaterial, the linear velocity Vc of the annular cutter 4 moving alongthe inclined edge of the cutter receiving member 5 and the angle ofinclination 0 of the edge of cutter receiving member 5 can be expressedby the following formula:

Sin 0 Vp/V c.

If suitable means for supporting the annular cutter is selected and anedge of the cutter receiving member is formed in a gentle curve, it willbe possible to cut the sheet material in the same shape as the curveand, if the sheet material is cut while being moved, it will be possibleto cut the sheet material in a shape corresponding to the curve.

Preferably, the material of the cutter receiving member is of higherhardness than the material of the annular cutter. If the annular cutteris caused to press against the cutter receiving member with a relativelygreat force, the sheet material can be cut easily even if an upper edge5c of the cutter receiving member 5 is worn and rounded as shown in FIG.5. The old and worn cutter receiving member 5 can be readily replaced bya new one by loosening the clamping screws 22,22. The old and wornannular cutter 4 can be readily replaced by a new one by removing thescrew 13 threaded into the shaft 12 (See FIG. 9).

The cutter receiving member may conveniently be in the fonn of a webhaving a greater length than the effective length of the cutterreceiving member. This permits to obviate the time-consuming operationof replacing the worn cutter receiving member by a new one, because theweb can be pulled in one direction to bring a new portion intoengagement with the annular cutter when the portion of the web servingas a cutter receiving member is worn. Preferably, the material of thisweb-like cutter receiving member is highly resilient, as in the casewith the material of the coiled spring of a clock, because it isconvenient to handle, since it can be wound in convolutions at oppositeends of the portion of the web used as a cutter receiving member.

If the annular cutter is not released from engagement with the cutterreceiving member when the former is returned to its starting position orif the annular cutter can be moved in reciprocating motion while beingmaintained in pressing engagement with the cutter receiving member, thenit is possible to cut a sheet material by the annular cutter in both itsadvance movement and its return movement. If a disc is used as a cutterreceiving member and the annular cutter is caused to press against itsperipheral edge, then it is possible to cut a sheet material in thecircular form. Means for driving the annular cutter in this case mayinclude a rotary shaft axially extending through the center of the discand mounting an arm which supports the annular cutter. It will beevident to one having an ordinary skill in the art that the annularcutter can be used in many different ways within the scope of thepresent invention.

What is claimed is:

1. An apparatus fur cutting a sheet material comprising a cutterreceiving member disposed to extend across the width of the sheetmaterial in contact with one surface thereof, an annular cutterrotatably mounted on a shaft arranged nearly normal to an edge of saidcutter receiving member so that said annular cutter presses at a portionof its peripheral edge against said edge, means supporting said shaft,and drive means operable to reciprocate said supporting means along saidcutter receiving member; said supporting means including a pivotal platesupporting said shaft; a sliding member pivotally supporting saidpivotal plate for pivoting about an axis in laterally spaced parallelrelation to said shaft; and means slidably supporting said slidingmember for reciprocation along said cutter receiving member; said drivemeans including an elongated element extending substantially parallel tosaid cutter receiving member and connected to said pivotal plate at apoint thereon substantially vertically above the pivot axis of saidpivotal member; whereby, when said element is moved in one directionalong said cutter receiving member, said pivotal plate is pivoted toswing said annular cutter downwardly into cooperating relation with saidcutter receiving member and, when said element is moved in the oppositedirection along said cutter receiving member, said pivotal plate ismoved in a direction to lift said annular cutter away from said cutterreceiving member; and means engageable with said pivotal plate to limitpivoting thereof in a direction to retract said annular cutter from saidcutter receiving member.

2. An apparatus for cutting a sheet material, as defined in claim 1,including a cylindrical member substantially fixed with respect to saidannular cutter to rotate therewith, said cylindrical member projectingover the upper surface of said cutter receiving member and limiting theamount of overlapping of said annular cutter and said cutter receivingmember.

3. An apparatus for cutting a sheet material, as defined in claim 1, inwhich said means slidably supporting said sliding member comprises guiderods extending substantially parallel to said cutter receiving member.

4. An apparatus for cutting a sheet material, as defined in claim 1, inwhich said elongated element comprises a wire.

5. An apparatus for cutting a sheet material comprising a cutterreceiving member disposed to extend across the width of the sheetmaterial in contact with one surface thereof, an annular cutterrotatably mounted on a shaft arranged nearly normal to an edge of saidcutter receiving member so that said annular cutter presses at a portionof its peripheral edge against said edge, means supporting said shaft,and drive means operable to reciprocate said supporting means along saidcutter receiving member; said supporting means comprising a pivotalplate supporting said shaft; a sliding member pivotally supporting saidpivotal plate for pivoting about an axis disposed in laterally spacedparallel relation to said shaft; guide rods supporting said slidingmember for reciprocation parallel to said cutter receiving member; awire extending substantially parallel to said cutter receiving memberand secured at an intermediate portion thereof, to said pivotal plate ata point disposed substantially vertically above the pivot axis of saidpivotal plate; said drive means comprising means operable to reciprocatesaid wire substantially parallel to said guide rods; said wire, whenmoving in one direction parallel to said guide rods, pivoting saidpivotal member to overlap said annular cutter with said cutter receivingmember and, when moved in the opposite direction, pivoting said pivotalmember to retract said annular cutter out of overlapping relation withsaid cutter receiving member; said support means further including acylindrical member substantially fixed with respect to said annularcutter to rotate therewith, and adapted to engage the upper surface ofsaid cutter receiving member to limit the amount of overlapping of saidannular cutter and said cutter receiving member; stop means engageablewith said pivotal member to limit the pivoting thereof in a directionretracting said annular cutter from overlapping relation with saidcutter receiver member; a spring positioned between said annular cutterand said pivotal plate and baising said annular cutter to engage aportion of its peripheral edge against the lateral surface of saidcutter receiver member; and a pusher plate fixed with respect to saidcutter receiving member at one end thereof and having a free endinclined with respect to the direction of movement of said annularcutter when said annular cu r is retracted from overlapping engagementwi sai cutter receiving mem r;

said pusher plate engaging the outer end of said cylindrical member tomove said cylindrical member toward said pivotal plate against the biasof said spring.

6. An apparatus for cutting a sheet material comprising a cutterreceiving member disposed to extend across the width of the sheetmaterial in contact with one surface thereof, an annular cutterrotatably mounted on a shaft arranged nearly normal to an edge of saidcutter receiving member so that said annular cutter presses at a portionof its peripheral edge against said edge, means supporting said shaft,and drive means operable to reciprocate said supporting means along saidcutter receiving member; said supporting means including a sphericalmember formed with an opening loosely receiving said shaft so that saidspherical member constitutes a bearing for said shaft; and meanssupporting said spherical member for angular displacement to adjust theangular relation of said shaft to said cutter receiving member.

7. An apparatus for cutting a sheet material as defined in claim 4,including a pulley to which one end of said wire is fastened; a secondpulley, of the same diameter as said first-mentioned pulley, to whichthe other end of said wire is connected; a pulley shaft having said twopulleys mounted at respective opposite ends thereof; and means operableto rotate said two pulleys in selected opposite directions.

8. An apparatus for cutting a sheet material as defined in claim '7, inwhich said shaft extends substantially parallel to said cutter receivingmember; said pulleys being fixedly secured to opposite ends of saidshaft for conjoint rotation in the same direction; said wire beingsecured to said pulleys in a direction such that it is wound on onepulley while being unwound from the other pulley responsive to rotationof said shaft; said driving means being operable to rotate said shaft inopposite angular directions to reciprocate said wire along said cutterreceiving member.

# i I 1 i

1. An apparatus fur cutting a sheet material comprising a cutterreceiving member disposed to extend across the width of the sheetmaterial in contact with one surface thereof, an annular cutterrotatably mounted on a shaft arranged nearly normal to an edge of saidcutter receiving member so that said annular cutter presses at a portiOnof its peripheral edge against said edge, means supporting said shaft,and drive means operable to reciprocate said supporting means along saidcutter receiving member; said supporting means including a pivotal platesupporting said shaft; a sliding member pivotally supporting saidpivotal plate for pivoting about an axis in laterally spaced parallelrelation to said shaft; and means slidably supporting said slidingmember for reciprocation along said cutter receiving member; said drivemeans including an elongated element extending substantially parallel tosaid cutter receiving member and connected to said pivotal plate at apoint thereon substantially vertically above the pivot axis of saidpivotal member; whereby, when said element is moved in one directionalong said cutter receiving member, said pivotal plate is pivoted toswing said annular cutter downwardly into cooperating relation with saidcutter receiving member and, when said element is moved in the oppositedirection along said cutter receiving member, said pivotal plate ismoved in a direction to lift said annular cutter away from said cutterreceiving member; and means engageable with said pivotal plate to limitpivoting thereof in a direction to retract said annular cutter from saidcutter receiving member.
 2. An apparatus for cutting a sheet material,as defined in claim 1, including a cylindrical member substantiallyfixed with respect to said annular cutter to rotate therewith, saidcylindrical member projecting over the upper surface of said cutterreceiving member and limiting the amount of overlapping of said annularcutter and said cutter receiving member.
 3. An apparatus for cutting asheet material, as defined in claim 1, in which said means slidablysupporting said sliding member comprises guide rods extendingsubstantially parallel to said cutter receiving member.
 4. An apparatusfor cutting a sheet material, as defined in claim 1, in which saidelongated element comprises a wire.
 5. An apparatus for cutting a sheetmaterial comprising a cutter receiving member disposed to extend acrossthe width of the sheet material in contact with one surface thereof, anannular cutter rotatably mounted on a shaft arranged nearly normal to anedge of said cutter receiving member so that said annular cutter pressesat a portion of its peripheral edge against said edge, means supportingsaid shaft, and drive means operable to reciprocate said supportingmeans along said cutter receiving member; said supporting meanscomprising a pivotal plate supporting said shaft; a sliding memberpivotally supporting said pivotal plate for pivoting about an axisdisposed in laterally spaced parallel relation to said shaft; guide rodssupporting said sliding member for reciprocation parallel to said cutterreceiving member; a wire extending substantially parallel to said cutterreceiving member and secured, at an intermediate portion thereof, tosaid pivotal plate at a point disposed substantially vertically abovethe pivot axis of said pivotal plate; said drive means comprising meansoperable to reciprocate said wire substantially parallel to said guiderods; said wire, when moving in one direction parallel to said guiderods, pivoting said pivotal member to overlap said annular cutter withsaid cutter receiving member and, when moved in the opposite direction,pivoting said pivotal member to retract said annular cutter out ofoverlapping relation with said cutter receiving member; said supportmeans further including a cylindrical member substantially fixed withrespect to said annular cutter to rotate therewith, and adapted toengage the upper surface of said cutter receiving member to limit theamount of overlapping of said annular cutter and said cutter receivingmember; stop means engageable with said pivotal member to limit thepivoting thereof in a direction retracting said annular cutter fromoverlapping relation with said cutter receiver member; a springpositioned between said annular cutter and said piVotal plate andbaising said annular cutter to engage a portion of its peripheral edgeagainst the lateral surface of said cutter receiver member; and a pusherplate fixed with respect to said cutter receiving member at one endthereof and having a free end inclined with respect to the direction ofmovement of said annular cutter when said annular cutter is retractedfrom overlapping engagement with said cutter receiving member; saidpusher plate engaging the outer end of said cylindrical member to movesaid cylindrical member toward said pivotal plate against the bias ofsaid spring.
 6. An apparatus for cutting a sheet material comprising acutter receiving member disposed to extend across the width of the sheetmaterial in contact with one surface thereof, an annular cutterrotatably mounted on a shaft arranged nearly normal to an edge of saidcutter receiving member so that said annular cutter presses at a portionof its peripheral edge against said edge, means supporting said shaft,and drive means operable to reciprocate said supporting means along saidcutter receiving member; said supporting means including a sphericalmember formed with an opening loosely receiving said shaft so that saidspherical member constitutes a bearing for said shaft; and meanssupporting said spherical member for angular displacement to adjust theangular relation of said shaft to said cutter receiving member.
 7. Anapparatus for cutting a sheet material as defined in claim 4, includinga pulley to which one end of said wire is fastened; a second pulley, ofthe same diameter as said first-mentioned pulley, to which the other endof said wire is connected; a pulley shaft having said two pulleysmounted at respective opposite ends thereof; and means operable torotate said two pulleys in selected opposite directions.
 8. An apparatusfor cutting a sheet material as defined in claim 7, in which said shaftextends substantially parallel to said cutter receiving member; saidpulleys being fixedly secured to opposite ends of said shaft forconjoint rotation in the same direction; said wire being secured to saidpulleys in a direction such that it is wound on one pulley while beingunwound from the other pulley responsive to rotation of said shaft; saiddriving means being operable to rotate said shaft in opposite angulardirections to reciprocate said wire along said cutter receiving member.